Generally, electrical/electronic devices should be subjected to performance tests for electrical operation after their manufacture in order to divide them into good products and defective products. For wafer-state semiconductor chips, packaged semiconductor chips and printed circuit boards, their performance tests can be performed only when the probe tips of probe card needles make electrical contact with the electrode pads of the chips.
As shown in FIG. 1, a probe card 20 comprises: printed circuit board 21 which makes electrical and mechanical connection with ZIF connectors or pogo-pins 12 mounted on a frog ring 11 of a test head 10; a probe ring 22 made of epoxy resin, fixed on the printed circuit board 21; a few thousand probe needles 23 bonded to the probe ring 22 with an epoxy adhesive and having tungsten probe tips 23a formed at first ends thereof, which make contact with the electrode pads of devices; and wires solder-connecting one end of each of the probe needles 23 to respective strip lines formed on the printed circuit board 21.
FIG. 2 schematically shows a state where a wafer 3 placed on a probe 2 is tested with the probe card 20 electrically connected to the tester 1.
The probe tips 23a are formed by forming first pointed ends of the probe needles 23 with a diameter of about 100 microns using chemical etching. To test the performance of a device, the pointed parts of the probe needles 23 make mechanical and electrical contact with the electrode pads of the device, in which the test is carried out using the elasticity and electrical conductivity of the probe needles 23.